A single bolt of lightning killed more than 300 reindeer that were huddled together during a severe thunderstorm Friday that ravaged the mountainous Hardangervidda plateau in southern Norway.

“They were lying there dead in a fairly concentrated area. Reindeer are pack animals and are often close together. During a heavy thunderstorm, they may have gathered even closer together out of fear,” Knut Nylend, of the Norwegian Nature Inspectorate, told the local news agency NTB.

More than 300 wild reindeer were killed by lightning in Hardangervidda, central Norway in what wildlife officials say was a highly unusual massacre by nature.